This invention relates generally to methods and apparatus for computed tomography (CT), and more particularly to methods and apparatus that provide for Bone Induced Spectral (BIS) artifact correction.
BIS artifacts are produced due to differential beam hardening owing to the presence of bone in an object being scanned. These artifacts cannot be corrected or accounted for using the traditional water based beam hardening correction. The non-linear spectral response in the detector can be characterized and corrected as long as the amount of bone in the object being scanned can be measured.
A significant artifact can be produced by a relatively small error in the projections. Like most CT artifacts, the center of the field of view of the detector is most sensitive to BIS artifacts.
Therefore, described below are methods and apparatus for correcting for BIS artifacts in the image space.